"If it were asked, why do we accept the theory of contagion, when already the divine law has refuted the notion of contagion, we will answer: The existence of contagion has been proved by experience, deduction, the senses, observation, and by unanimous reports. And it is not a secret to whoever has looked into this matter or has come to be aware of it that those who come into contact with plague patients mostly die, while those who do not come into contact survive. And amidst the horrible afflictions that the plague has imposed upon the people, God has afflicted the people with some learned religious scholars who issue fatwas* against fleeing the plague, so that the quills with which the scholars wrote these fatwas were like swords upon which the Muslims died. In conclusion, to ignore the proofs of plague contagion is an indecency and an affront to God and holds cheap the lives of Muslims."

*rulings on Islamic law

Lisan al-Din Ibn al-Khatib, A Very Useful Inquiry into the Horrible Sickness, Granada, Spain, 1349-1352

The outbreaks of plague described in the passage led most directly to which of the following?